/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header Styles */
.hero {
    text-align: center;
    padding: 80px 0 60px;
    color: white;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 20px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 300;
    margin-bottom: 30px;
    opacity: 0.9;
}

.hero-description {
    max-width: 600px;
    margin: 0 auto;
    font-size: 1.1rem;
    opacity: 0.8;
}

/* Main Content */
.main-content {
    background: white;
    border-radius: 20px;
    padding: 60px 40px;
    margin-bottom: 40px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.1);
}

/* Pace Charts Section */
.pace-charts {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 40px;
    margin-bottom: 80px;
}

.chart-card {
    background: #f8f9fa;
    border-radius: 16px;
    padding: 40px;
    text-align: center;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.chart-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px rgba(0,0,0,0.1);
    border-color: #667eea;
}

.chart-icon {
    font-size: 3rem;
    margin-bottom: 20px;
}

.chart-card h2 {
    font-size: 1.8rem;
    font-weight: 600;
    margin-bottom: 15px;
    color: #2d3748;
}

.chart-card p {
    color: #718096;
    margin-bottom: 30px;
    line-height: 1.6;
}

.chart-button {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 15px 30px;
    border-radius: 50px;
    font-size: 1.1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
}

.chart-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(102, 126, 234, 0.3);
}

.marathon-button {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.half-marathon-button {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
}

.half-marathon-button:hover {
    box-shadow: 0 10px 20px rgba(245, 87, 108, 0.3);
}

/* Calculator Section */
.calculator-section {
    text-align: center;
}

.calculator-section h2 {
    font-size: 2.2rem;
    font-weight: 600;
    margin-bottom: 40px;
    color: #2d3748;
}

.calculator-card {
    background: #f8f9fa;
    border-radius: 16px;
    padding: 40px;
    max-width: 600px;
    margin: 0 auto;
}

.calculator-inputs {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.input-group {
    text-align: left;
}

.input-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: #4a5568;
}

.input-group input,
.input-group select {
    width: 100%;
    padding: 12px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.input-group input:focus,
.input-group select:focus {
    outline: none;
    border-color: #667eea;
}

.calculate-button {
    background: linear-gradient(135deg, #48bb78 0%, #38a169 100%);
    color: white;
    border: none;
    padding: 15px 40px;
    border-radius: 50px;
    font-size: 1.1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-bottom: 30px;
}

.calculate-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(72, 187, 120, 0.3);
}

.pace-result {
    background: white;
    border-radius: 12px;
    padding: 20px;
    border: 2px solid #e2e8f0;
    text-align: left;
    display: none;
}

.pace-result.show {
    display: block;
}

.pace-result h3 {
    color: #2d3748;
    margin-bottom: 15px;
    font-size: 1.3rem;
}

.pace-item {
    display: flex;
    justify-content: space-between;
    padding: 8px 0;
    border-bottom: 1px solid #e2e8f0;
}

.pace-item:last-child {
    border-bottom: none;
}

.pace-label {
    font-weight: 500;
    color: #4a5568;
}

.pace-value {
    font-weight: 600;
    color: #2d3748;
}

/* Footer */
.footer {
    text-align: center;
    padding: 40px 0;
    color: white;
    opacity: 0.8;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.2rem;
    }
    
    .main-content {
        padding: 40px 20px;
    }
    
    .pace-charts {
        grid-template-columns: 1fr;
        gap: 30px;
    }
    
    .chart-card {
        padding: 30px 20px;
    }
    
    .calculator-inputs {
        grid-template-columns: 1fr;
    }

    .chart-button {
        width: 100%;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: 60px 0 40px;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .main-content {
        padding: 30px 15px;
    }
    
    .chart-card {
        padding: 25px 15px;
    }

    .calculator-card {
        padding: 24px 16px;
    }

    .hero-description {
        font-size: 1rem;
    }

    .chart-button {
        width: 100%;
    }
}